JPH03221588A - Compounding agent for liquid crystal composition and liquid crystal composition containing same agent - Google Patents

Abstract

PURPOSE:To obtain the title compounding agent providing an electro-optic element having excellent speed of response, orientation and contrast, containing a specific optically active compound. CONSTITUTION:The objective compounding agent containing an optically active compound [e.g. optically active 4 (4''-fluoroalkyloxybiphenyl-4'-carbonyloxy) benzoic ester of haloalkyl-2-alkanol] shown by the formula [R1 is 1-18C fluoroalkyl; R2 is 1-16C alkyl; R3 is C2F5, CF3, CHF2 or CH2F; X is O, COO, OCO or single bond; Y is COO, OCO, CH2O or OCH2; Z is COO or O; (A) and (B) are cyclic group; * is center of optical activity].

Description

DETAILED DESCRIPTION OF THE INVENTION [Prior Art] In recent years, TN type liquid crystal display elements have been widely used as display systems for watches, calculators, and the like. The liquid crystal material used in this display method is a nematic or nematic-cholesteric liquid crystal, and the dynamic force that moves molecules in response to an electric field is essentially based on the dielectric anisotropy of the liquid crystal molecules, so the response speed is It has fundamental problems such as being slow and difficult to drive at high multiplexes.

Recently, smectic liquid crystals, particularly chiral smectic liquid crystals exhibiting ferroelectricity, have been actively researched as having the potential to overcome these problems. The reason for this is that smectic liquid crystals, especially ferroelectric liquid crystals, were developed by C1ar in 1980.
Since K and Lagavall reported extremely important characteristics for display devices, such as ■sub-microsecond high-speed response, ■memory characteristics due to bistableness, and ■existence of write threshold voltage, new display devices have been developed. It has started to attract a lot of attention as a material, and attempts are being made to apply it to large-capacity displays, memory-type displays, and light modulation elements.

Practical performance required of liquid crystal materials, especially ferroelectric liquid crystals, is: 1. Chemically and photochemically stable, and excellent in durability. ■Shows a wide range of liquid crystal phases from low to high temperatures, and exhibits ferroelectricity over a wide temperature range including room temperature. ■The rotational viscosity of liquid crystal molecules is low, and the spontaneous polarization is large, allowing for high-speed response. ■The magnitude of the birefringence is suitable for increasing display contrast. ■The balance of elastic modulus is suitable for dynamic parking. (2) It has an appropriate tilt angle and can provide high display contrast.

Although various liquid crystal materials have been synthesized based on these material designs, there is currently no single liquid crystal material that can satisfy all the characteristics. For this reason, in practice, liquid crystals are not used as single liquid crystals, but at least several to more than ten types of liquid crystal materials are blended to create a multi-component mixed liquid crystal material to achieve the characteristics and functions required for liquid crystal display systems. are doing.

Currently, there are two main methods for mixing and blending systems to appropriately adjust the material properties of ferroelectric liquid crystals: one is to mix multiple liquid crystals that exhibit a chiral smectic phase, and the other is to mix multiple liquid crystals that exhibit a smectic phase. This method involves adding a compounding agent (hereinafter referred to as chiral dopant).

In the former case, it can be said that expansion of the temperature range exhibiting the chiral smectic C phase and large spontaneous polarization reflected in the response speed to an applied electric field can be relatively easily adjusted to the required physical properties. However, the molecular structure of liquid crystal compounds with large spontaneous polarization is such that the dipole is located close to the asymmetric carbon, and although the spontaneous polarization is large, the rotational viscosity of the liquid crystal molecules also tends to be high. It is difficult to obtain a fast enough response. In the latter method, the liquid crystal or liquid crystal composition (referred to as base liquid crystal) exhibiting a smectic C phase, which is the main component, does not need to be optically active itself, but is mixed and adjusted in various ways to satisfy the characteristics required for the liquid crystal display method. be done. Chiral smectic C
This is a method for adjusting ferroelectric liquid crystal materials without impeding high-speed response by inducing phase and appropriate spontaneous polarization.

According to the latter method, a liquid crystal composition with a low viscosity is prepared in the base liquid crystal, and a chiral dopant is added to control the spontaneous polarization and the helical pitch of the chiral smectic C phase, thereby improving the response speed of the electro-optical element. , it is possible to obtain good orientation and contrast, and it is becoming mainstream as a manufacturing technology for practical materials. From such a technical viewpoint, there is a need for a parent liquid crystal and a chiral dopant made of an optically active or non-optically active compound that exhibit excellent performance.

〔the purpose〕

An object of the present invention is to provide a novel and excellent ferroelectric liquid crystal, a compounding agent for a liquid crystal composition, and a novel liquid crystal composition containing the same.

〔composition〕

One of the aspects of the present invention is the general formula % [1] [R, is 1-18 fluoroalkyl group R2 is 1-18]
16 alkyl group R3 is 02F5, CF, , CHF2 or CH2FX
is 0, COO1OCO or single bond Y is Coo,
OCO, CH2O or 0CH2Z is COO or 0 (A), (B) are selected from cyclic groups.

Bobble shows optically active center. ] The present invention relates to a liquid crystal compound or a compounding agent for a liquid crystal composition, which is an optically active compound represented by the following.

Another aspect of the present invention relates to a liquid crystal composition containing at least one of the above compounds, particularly a liquid crystal composition exhibiting a chiral smectic phase.

Examples of the cyclic group include cyclic groups such as these, in which 1 to 4 hydrogen atoms of these cyclic groups are F, or CQ, Br, C'N group, NO2 group, and CF , may be substituted with a group.

In the above-mentioned membrane type [1], the R0 group is a fluoroalkyl group having 1 to 18 carbon atoms, preferably a fluoroalkyl group having 4 to 16 carbon atoms, i.e., n-butyl group, n-pentyl group, n-hexyl group. , n-heptyl group, n-octyl group, n-nonyl group, D-decyl group, n-undecyl group,
Groups in which fluorine is introduced into a straight chain alkyl group such as n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, especially straight-chain alkyl groups. Examples include those in which part of the chain is perfluorinated. In particular, c, p2. −
, -(cH,)i- (where Q=1 to 12. k =
Fluoroalkyl groups represented by O-2) are suitable.

R2 represents a linear alkyl group, a branched alkyl group, or an aralkyl group. The linear alkyl group and branched alkyl group are preferably linear alkyl groups and branched alkyl groups having 1 to 12 carbon atoms, i.e., n-propyl group, n-
Butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-1-lysosyl group, n-tetradecyl group, n-pentadecyl group, n-
Hexadecyl group, n-heptadecyl group, n-octadecyl group, 1-methylbutyl group, 2-methylbutyl group, 3-
Examples include methylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 1-methylhexyl group, and 1-methylheptyl group. Examples of the aralkyl group include a phenyl group, a benzyl group, a phenethyl group, and a substituted phenyl group.

R3 is CH, l, Fn (m+n=3tm=o+1t2
．． 3), C2F5. CCQF, CC sentence, F, C
Indicates CQ3゜CF3CCO2 etc.

An example of one-boat fishing synthesis of the target compound of the present invention is shown.

An optically active haloalkyl-2-alkanol is reacted with benzyloxybenzoic acid chloride to produce an ester, which is then hydrogenated using a catalyst such as palladium on carbon to obtain a phenol derivative (2) of the optically active haloalkyl-2-alkanol. ) is manufactured.

HO-◎-COO-CH-R2 Ning (R2, R, are the same as above.

The acid chloride of 4-fluoroalkyloxy-47-biphenylcarboxylic acid [3] represented by the above phenol derivative [2] general formula) % formula % [3]) is mixed with a base such as pyridine, dimethylamine and triethylamine. The target compound, optically active haloalkyl-2-alkanol, is reacted in an inert solvent such as methylene chloride, tetrahydrofuran, or diethyl ether in the presence of 4-
(4'-fluoroalkyloxybiphenyl-4'-carbonyloxy)benzoic acid ester can be produced.

Alternatively, the compound of the present invention may be a phenol derivative of optically active haloalkyl-2-alkanol [2] and 4
-Fluoroalkyloxy-4'-biphenylcarboxylic acid [3] can be produced by carrying out an ester reaction using a dehydration condensation agent such as dicyclohexylcarbodiimide.

The optically active compound is an enantiomer whose absolute structure includes both (R) monolithic and (S) monolithic structures, and its optical purity is preferably 100% enantioexcess, but its optical purity is not particularly defined.

The compounds of the present invention include optically active haloalkyl-2-
Examples include the following compounds derived from alkanols.

4-fluoroalkylbenzoic acid ester 4-fluoroalkyloxybenzoic acid ester 4-fluoroalkylcyclohexylcarboxylic acid ester 4-fluoroalkyloxycyclohexylcarboxylic acid ester 4-fluoroalkyl-4'-biphenylcarboxylic acid ester 4- Fluoroalkoxy-4・'-biphenylcarboxylic acid ester phenyl ether 4-(4-fluoroalkoxybenzoyloxy)phenyl ether ester ester phenyl ester phenyl ester syl ester 4-fluoroalkyl-4'-monobiphenyl grouppoterether ether phenyl Ether phenyl ether ether sil ether xyl carbonyl-4-biphenyl ester ester ester ster ester steryl 4-fluoroalkyl benzoic@-4'-alkoxy-4
-cyclohexyl phenyl ester oxy) cyclohexyl carboxylic acid ester lene) phenyl ether x) cyclohexyl ether lene) cyclohexyl ether tyrene) cyclohexyl ester ester ester ester lene oxy) biphenyl nial 4-(4-fluoro Alkylcyclohexylphenyloxycarbonyl)benzoic acid ester tylarsicarbonyl)hyphenyleal Furthermore, compounds in which alkyl and alkoxy in the exemplified compounds represent the corresponding alkoxycarbonyl, alkylcarbonyloxy, and alkanoyl, respectively, are also included.

〔Example〕

Next, the present invention will be explained with reference to examples, but the present invention is not limited thereto.

Example-1 To 5 m of a methylene chloride solution containing 0.56 g of 4-benzyloxybenzoic acid chloride, 0.38 g of (R)-(+)-1-trifluoromethylheptatool and 0.23 g of triethylamine were added to methylene chloride. A solution dissolved in 5 mQ was gradually added under water cooling. After returning to room temperature and stirring for 12 hours, the reaction solution was poured into ice water and extracted with methylene chloride. The methylene chloride phase was washed with diluted hydrochloric acid, water, 1N sodium carbonate, and water in this order, and then dehydrated with anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain a crude product.

This crude product was treated by silica gel column chromatography to obtain 0.5% of (R)-(+)-4-benzyloxybenzoic acid 1-trifluoromethylheptyl ester
3 g was obtained.

This product and 0.13 g of 10% palladium on carbon were added to ethanol to perform a debenzylation reaction in a hydrogen atmosphere, and 0.13 g of (R)-(+)-4-hydroxybenzoic acid 1-trifluoromethylheptyl ester was added to ethanol. 39 g was obtained.

(rubonyl) phenyl ester bromide-IH,IH-perfluorobutane 0.44 g,
Methyl 4-hydroxy-4'-biphenylcarboxylate 0
．． 33 g and 0.49 g of potassium carbonate were added to 20 mQ of acetone solvent, and the mixture was stirred and reacted under reflux for 8 hours. Next, the reaction solution was added to 100 mQ of cold water, the white precipitate was collected by filtration, and purified by recrystallization to obtain 4-IH,
0.65 g of methyl LH-perfluorobutyloxy-4/biphenylcarboxylate was obtained. This product was ester-hydrolyzed using a conventional method to obtain 4-IH.

After making IH-perfluorobutyloxy-47-biphenylcarboxylic acid, it was chlorinated with thionyl chloride,
4-1)1. 0.65 g of IH-perfluorobutyloxy 4'-biphenylcarboxylic acid chloride was obtained.

(R)-(+)-4-hydroxyamma synthesized in the previous section,
Framic acid 2-trifluoromethylheptyl ester 0.39
4-IH under water cooling.

1) A methylene chloride solution containing 0.65 g of 1-perfluorobutyloxy-4'-biphenylcarboxylic acid chloride] OmR was gradually added. After returning to room temperature and stirring for a day and night, the reaction solution was poured into water and extracted with methylene chloride. The methylene chloride phase was washed with diluted hydrochloric acid, water, 1N sodium carbonate, and water in this order. After dehydration with anhydrous magnesium sulfate, the solvent was removed. After distilling off under reduced pressure, the residue was purified by silica gel column chromatography to obtain 0.57 g of the target compound.

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram of the target compound of the present invention (KB
r method) is shown in Figure 1.

Example-2 C.F.

(R)-(+)-C, F engineering, -(CI+□)2-0-
@-@-Coo-O-COO-CH-C&H1° ratio 411 in place of 4-IH, 1,11-perfluorobutyloxy-4'-biphenylcarboxylic acid in Example-1
(,IH,2H,2H-perfluorooctyloxy-
The target compound was produced in a similar manner using 4'-biphenylcarboxylic acid.

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum g diagram of the target compound of the present invention (KB
r method) is shown in Figure 2.

Example-3 10 parts by weight of the compound of Example-1 (I!!i component No. 2) and 90 parts by weight of a liquid crystal compound (component No. 1) having a smectic C phase (S''C phase) were mixed. A liquid crystal composition was prepared.This liquid crystal composition was filled between glass substrates (gap 2.2 μm) made of IT○ transparent polarized glass substrates coated with a polyimide alignment film so that the rubbing directions were parallel to each other. 0.1 to 1.0 on a temperature controlled hot stage.
After cooling at a rate of 0℃/1 minute and observing the phase transition behavior using a polarizing microscope equipped with a photomultiplier, the following coating was obtained.
The smectic A phase was oriented as shown in FIG.

When a voltage of ±30 V was applied to this cell and the optical response was measured, an electroclinic effect was observed in the smectic A phase, and an extremely fast optical response of 18 μ5 ec (Tc - T = 30 °C) was observed in the xyl smectic C phase. A good contrast was obtained. Similar effects can be obtained with the compounds of other examples, and the compound of the present invention is a compound useful as a component liquid crystal of a mixed liquid crystal composition consisting of multiple components.

(The following is a blank space) [Effects] The optically active compound of the present invention can itself be an important and useful material as a ferroelectric liquid crystal compound or as a chiral dopant as one component of a ferroelectric liquid crystal composition. .

(2) The liquid crystal compound and liquid crystal composition of the present invention have good responsiveness to an applied electric field as a ferroelectric liquid crystal, and can be applied to liquid crystal display elements, liquid crystal optical shutters, and nonlinear optical functional materials.

(2) The liquid crystal compound and liquid crystal composition of the present invention exhibit an electroclinic effect showing an optical response to an applied electric field in the smectic A phase, and can be applied to light valves and electro-optic shutters.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 show infrared absorption spectra of the compounds obtained in Example-1 and Example-2.

Claims (1)

[Claims] 1. General formula▲ Numerical formulas, chemical formulas, tables, etc.▼... [1] [R_1 is 1 to 18 fluoroalkyl group R_2 is,
1 to 16 alkyl group R_3 is C_2F_5, CF_3, CHF_2 or CH_2FX is O, COO, OCO or single bond Y is COO, OCO, CH_2O or OCH_2Z
is COO or O. (A), (B) are selected from cyclic groups. ^* indicates an optically active center. ] A liquid crystal compound or a compounding agent for a liquid crystal composition, which is an optically active compound represented by the following. 2. A liquid crystal composition containing at least one compound according to claim 1.